Letter to the Editor

The mumps neutralizing antibody titration as performed in our laboratory accurately predicts susceptibility to mumps. No patient with a titer of 1:2 or greater has subsequently become infected. When a group of children was exposed to mumps on a long-stay hospital ward, every seronegative individual subsequently excreted virus, developed parotitis, or both.1 On the other hand we know of numerous skin test positive individuals who went on to develop mumps. The results of our study indicate that placebo reactions cannot account for all of the discrepancies in the mumps skin test.